Electroluminescent (EL) devices

ABSTRACT

An electroluminescent device containing an anode, an organic electroluminescent element, and a cathode wherein the electroluminescent element contains, for example, a fluorescent hydrocarbon component of Formula (I)wherein R1 and R2 are substituents, which are selected from the group consisting of hydrogen, an alkyl, an alicyclic alkyl, an alkoxy, a halogen, and a cyano; Ar1 and Ar2 are each independently an aromatic component or an aryl group comprised of a from about 4 to about 15 conjugate-bonded or fused benzene rings.

RELATED COPENDING APPLICATIONS AND PATENTS

Illustrated in copending applications U.S. Ser. No. 09/770,159, filedconcurrently herewith, the disclosure of which is totally incorporatedherein by reference, is an organic light emitting device comprising inan optional sequence

(i) a substrate;

(ii) a first electrode;

(iii) a mixed region comprising a mixture of a hole transport materialand an electron transport material, and wherein this mixed regionincludes at least one organic luminescent material;

(iv) a second electrode;

(v) a thermal protective element coated on the second electrode;wherein, one of the two said first and second electrodes is a holeinjection anode, and one of the two said electrodes is an electroninjection cathode, and wherein the organic light emitting devicesfurther comprises;

(vi) a hole transport region, interposed between the anode and the mixedregion, wherein the hole transport region optionally includes a bufferlayer; and

(vii) an electron transport region interposed between the secondelectrode and the mixed region; and in U.S. Ser. No. 09/770,154, filedconcurrently herewith, the disclosure of which is totally incorporatedherein by reference, is an organic light emitting device comprising insequence

a substrate;

a first electrode;

a light-emitting region comprising an organic luminescent material; and

a second electrode.

Illustrated in U.S. Pat. Nos. 5,942,340; 5,952,115; 5,932,363;5,925,472, and 5,891,587, the disclosures of which are totallyincorporated herein by reference, are EL devices. In U.S. Pat. No.5,925,472, the disclosures of which are totally incorporated herein byreference, there are disclosed organic EL devices with blue luminescentmaterials comprised of metal chelates of oxadiazole compounds, and whichdevices may provide a greenish blue color.

Illustrated in U.S. Pat. No. 6,057,048, the disclosure of which istotally incorporated herein by reference, is an electroluminescentdevice comprised of an anode, a hole transporting layer, a lightemitting layer, and a cathode, wherein said light emitting layercontains a component of the

wherein Ar¹, Ar², Ar³, and Ar⁴ are each independently aryl or optionallyaliphatic; R¹ and R² are independently selected from the groupconsisting of hydrogen, aliphatic, halogen, and cyano; L is a suitablelinking group; and n is a number of from 0 to about 3.

The appropriate components and processes of the above patents andcopending applications may be selected for the present invention inembodiments thereof.

BACKGROUND OF THE INVENTION

This invention is directed to organic electroluminescent (EL) devices,and more specifically, to organic EL devices with a number of excellentperformance characteristics inclusive of the enablement of blue emittingEL devices, which devices contain luminescent components or aluminescent component with excellent high thermal stability, filmforming characteristics and intense blue fluorescence. Organic ELdevices are desired that are capable of providing uniform luminescence,saturated color especially in the blue regions of the visible spectrum,and low driving voltages. The organic EL devices of the presentinvention enable in embodiments the above characteristics and whichdevices contain organic luminescent materials or light emittingcomponents comprised of fluorescent hydrocarbon compounds, and whichdevices can be selected for use in flat-panel emissive displaytechnologies, including TV screens, computer screens, and the like.

PRIOR ART

A simple organic EL device can be comprised of a layer of an organicluminescent material conductively sandwiched between an anode, typicallycomprised of a transparent conductor, such as indium tin oxide, and acathode, typically a low work function metal such as magnesium, calcium,aluminum, or the alloys thereof with other metals. The EL devicefunctions on the principle that under an electric field, positivecharges (holes) and negative charges (electrons) are respectivelyinjected from the anode and cathode into the luminescent layer andundergo recombination to form excitonic states which subsequently emitlight. A number of prior art organic EL devices have been prepared froma laminate of an organic luminescent material and electrodes of oppositepolarity, which devices include a single crystal material, such assingle crystal anthracene, as the luminescent substance as described,for example, in U.S. Pat. No. 3,530,325. However, these devices usuallyrequire excitation voltages on the order of 100 volts or greater.

In U.S. Pat. No. 4,539,507 there is disclosed an EL device formed of aconductive glass transparent anode, a hole transporting layer of1,1-bis(4-p-tolylaminophenyl)cyclohexane, an electron transporting layerof 4,4′-bis(5,7-di-tert-pentyl-2-benzoxzolyl)stilben, and an indiumcathode.

U.S. Pat. No. 4,720,432 discloses an organic EL device comprising adual-layer hole injecting and transporting zone, one layer beingcomprised of porphyrinic compounds supporting hole injection and theother layer being comprised of aromatic tertiary amine compoundssupporting hole transport.

U.S. Pat. No. 4,769,292 discloses an EL device employing a luminescentzone comprised of an organic host material capable of sustaininghole-electron recombination and a fluorescent dye material capable ofemitting light in response to energy released by hole-electronrecombination. A preferred host material is an aluminum complex of8-hydroxyquinoline, namely tris(8-hydroxyquinolinate)aluminum.

While recent progress in organic EL research has elevated the potentialof organic EL devices for widespread applications, the performancelevels of a number of current available devices, especially with respectto blue emission, may still be below expectations. Further, for visualdisplay applications, organic luminescent materials should provide asatisfactory color in the visible spectrum, normally with emissionmaxima at about 460, 550 and 630 nanometers for blue, green and red.These organic EL devices may comprise a light-emitting layer which iscomprised of a host material doped with a guest fluorescent materialthat is responsible for color emission. For efficient down-shifting ofEL emission wavelength in the host-guest emitting layer, it may bedesirable that the host material should fluorescence in the blue orshorter wavelength region. In many conventional organic EL devices, theluminescent zone or layer is formed of a green-emitting luminophor oftris(8-hydroxyquinolinate)aluminum with certain fluorescent materials.U.S. Pat. No. 5,409,783 discloses a red-emitting organic EL device bydoping the tris(8-hydroxyquinolinate)aluminum layer with a redfluorescent dye. However, up-shifting of thetris(8-hydroxyquinolinate)aluminum emission to blue region is believedto be highly inefficient. Although there have been several disclosuresdescribing blue-emitting organic EL devices, for example in U.S. Pat.Nos. 5,151,629 and 5,516,577, the disclosures of which are totallyincorporated herein by reference, their performance characteristicsstill possess many disadvantages such as poor emission hue, highoperation voltages, low luminance, and poor operation stability. Thus,there continues to be a need for improved luminescent compositions fororganic EL devices, which may vacuum evaporable and form thin films withexcellent thermal stability. There is also a need for luminescentcompositions which are capable of providing uniform and satisfactoryemission in the blue region of the light spectrum. In particular, thereis a need for efficient blue luminescent materials for organic ELdevices, which may optionally be doped with a fluorescent dye. Further,there is also a need for luminescent compositions which can enhancecharge transporting characteristics, thus lowering device drivingvoltages. Therefore, a primary feature of the present invention is toprovide luminescent materials comprised of certain fluorescenthydrocarbon compounds, which in comparison to certain EL devicescomprised of the metal chelates of oxadiazole compounds can provideimproved and excellent emission characteristics particularly in the blueregion, such as a saturated blue color and a narrow emission spectrum.

SUMMARY OF THE INVENTION

It is a feature of the present invention to provide luminescentcompositions for organic EL devices.

It is another feature of the present invention to provide organic ELdevices with many advantages, such as low operation voltages, uniformlight emission with spectrum spreading from blue to longer wavelengths,thermal stability, electrochemical stability, and charge transportcapability.

In an another feature of the present invention there are providedorganic EL devices with a light emitting layer containing a luminescentmaterial comprised of novel fluorescent hydrocarbon compounds.

In yet another feature of the present invention there are providedorganic EL devices with a light-emitting layer comprised of aluminescent hydrocarbon compound.

Further, in a feature of the present invention there are providedorganic EL devices comprised of a supporting substrate of, for example,glass, an anode, an optional buffer layer, a vacuum deposited organichole transporting layer comprised of, for example,4,4′-bis-(9-carbazolyl)-1,1-biphenyl, a vacuum deposited light emittinglayer comprised of a luminescent hydrocarbon compound, an optionalvacuum deposited electron transporting layer, and in contact therewith alow work function metal, such as magnesium, lithium, and their alloys asa cathode.

Yet in another feature of the present invention there is provided anorganic EL device comprised of a supporting substrate of, for example,glass, an anode, an optional buffer layer, a vacuum deposited organichole transporting layer comprised of tertiary aromatic amines, forexample, N,N′-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine, avacuum deposited light emitting layer, an optional vacuum depositedelectron transporting layer, and in contact therewith a low workfunction metal, such as magnesium and its alloys as a cathode, whereinthe light emitting layer is comprised of a mixture of a novelhydrocarbon compound as a host component and an optional fluorescentmaterial.

These and the other features of the present invention are accomplishedby the provision of luminescent or light emitting components comprisedof the hydrocarbon compounds illustrated by the Formula (I)

wherein R¹ and R² are substituents, which may be selected from the groupconsisting of hydrogen, an alkyl group with, for example, from 1 toabout 25, and more specifically, to about 6 carbon atoms, an aryl groupwith about 6 to about 30 carbon atoms, an alkoxy group with from 1 toabout 25, and more specifically, to about 6 carbon atoms, a halogen, acyano group and the like; Ar¹ and Ar² are each an aromatic component,such as an aryl group with, for example, about 4 to about 10conjugate-bonded or fused benzene rings, and which may be independentlyselected, for example, from the group consisting of those as representedby or encompassed by the following formulas

wherein R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ are each a substituent selected fromthe group consisting of hydrogen, an alkyl group with, for example, from1 to about 6 carbon atoms, an alicyclic alkyl group with from about 3 toabout 15 carbon atoms, an alkoxy group with, for example, preferablyfrom 1 to about 6 carbon atoms, a dialkylamino group with preferablyfrom about 1 to about 3 carbon atoms, a halogen, a cyano group and thelike.

The features of the present invention can be also accomplished by theprovision of luminescent or light emitting components comprised of thehydrocarbon compounds illustrated by Formula (II)

wherein R¹ and R² are substituents, which may be selected from the groupconsisting of hydrogen, an alkyl group with, for example, preferablyfrom 1 to about 6 carbon atoms, an alicyclic alkyl group with from about3 to about 15 carbon atoms, an aryl group with about 6 to about 30carbon atoms, an alkoxy group with preferably from 1 to about 6 carbonatoms, a halogen, a cyano group and the like; R³, R⁴, R⁵, and R⁶ areeach a substituent, which may be selected from the group consisting ofhydrogen, an alkyl group with, for example, preferably from 1 to about 6carbon atoms, an alicyclic alkyl group with from about 3 to about 15carbon atoms, an aryl group with about 6 to about 30 carbon atoms, analkoxy group with preferably from 1 to about 6 carbon atoms, and thelike, wherein R³ and R⁴, or R⁴ and R⁵ may optionally be combined into abivalent hydrocarbon group, and is, for example, selected from the groupconsisting of an alkylene group with from about 3 to about 8 carbonatoms, an alkylidene group with from about 3 to about 15 carbon atoms,an alicyclic alkylidene group with from about 3 to about 15 carbonatoms, and a arylalkylidene group with from about 6 to about 30 carbonatoms, and the like; Ar¹ and Ar² are each an aromatic component, such asan aryl group with from about 6 to about 30 carbon atoms, or anarylvinyl group with from about 6 to about 30 carbon atoms, which may,for example, be selected from the group consisting of a phenyl, abiphenylyl, a 3,5-diarylphenyl, a phenylvinyl, a diphenylvinyl, and thelike; and wherein Ar is a tetravalent aromatic group with, for example,from about 6 to about 60 carbon atoms, and which group may selected, forexample, from the group consisting of the following formulas

wherein R₁₁, R₁₂, and R₁₃ are each a substituent, which may be selectedfrom the group consisting of hydrogen, an alkyl group with, for example,preferably from 1 to about 6 carbon atoms, an alicyclic alkyl group withfrom about 3 to about 15 carbon atoms, an alkoxy group with, forexample, preferably from 1 to about 6 carbon atoms, a dialkylamino groupwith preferably from about 1 to about 3 carbon atoms, a halogen, a cyanogroup and the like.

In embodiments, the present invention relates to organic EL devices thatare comprised in the following order of a supporting substrate of, forexample, glass, an anode, an optional buffer layer, an organic holetransporting layer, an organic light emitting hydrocarbon layer, and anoptional electron transporting layer, and in contact therewith a lowwork function metal as a cathode, wherein the light emitting layercontains at least one luminescent hydrocarbon compound illustrated andencompassed by the formulas recited herein, for example (I) and (II);and layered EL devices with a light emitting layer comprised of aluminescent composition comprised of a hydrocarbon compound illustratedby, for example, Formulas (I) and (II) as a host component capable ofsustaining hole-electron recombination and a guest fluorescent materialcapable of emitting light in response to energy released by thehole-electron recombination. The light emitting layer may be formed byvacuum deposition from evaporation of the fluorescent hydrocarbonmaterial, and wherein the presence of the fluorescent material permits awide latitude of wavelengths of light emission and may enable theenhancement of electroluminescent efficiency and improvements in deviceoperation stability.

The luminescent or light emitting hydrocarbon materials illustratedherein possess in embodiments several advantages. For example, thehydrocarbon compounds exhibit strong fluorescence in the solid state inthe region of from about 400 nanometers to longer wavelengths of, forexample, about 600 nanometers; they have the ability of forming thinfilms with excellent thermal stability by vacuum evaporation; they arestable; and they can also be blended with a number of fluorescentmaterials to form a common phase.

FIGURES

The FIGURE illustrates an EL device or an organic light emitting diodewhich is comprised of a supporting substrate 1 of, for example, glass;an anode 2 of, for example, indium tin oxide in a thickness of fromabout 1 to about 100 nanometers and preferably from about 10 to about 80nanometers (throughout the thickness ranges for each layer are examplesand other suitable thickness may be selected); optionally a buffer layer3 of, for example, copper (II) phthalocyanine in a thickness of fromabout 5 to about 80 nanometers and preferably from about 10 to about 40nanometers; an organic hole transporting layer 4 of an aromatic aminecompound, for exampleN,N′-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl4,4′-diamine in a thicknessof from about 1 to about 100 nanometers and preferably from about 5 toabout 80 nanometers; an organic light emitting layer 5 comprised of aluminescent hydrocarbon compound of the formulas or encompassed by theformulas illustrated herein in a thickness of from about 1 to about 100nanometers and preferably from about 20 to about 80 nanometers; anorganic electron transporting layer or hole blocking layer 6 of, forexample, 4,4′-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′-biphenyl ortris-(8-hydroxyquinolinato)aluminum in a thickness of from about 1 toabout 300 nanometers and preferably from about 10 to about 80nanometers, and in contact therewith a low work function metal as acathode 7. In this EL device, a junction is formed between the holetransporting layer and the light emitting layer. In operation, when theanode is electrically biased to a positive potential with respect to thecathode, holes are injected into the organic hole transporting layer andtransported across this layer to the junction. Concurrently, electronsare injected from the cathode to the electron transport layer and aretransported toward the same junction. Recombination of holes andelectron occurs near the junction resulting in light emission.Optionally, the light emitting layer can contain more than oneluminescent hydrocarbon compound illustrated and encompassed by theFormulas recited herein, for example (I) and (II); and layered ELdevices with a light emitting layer comprised of a luminescentcomposition comprised of a hydrocarbon compound illustrated by, forexample, Formulas (I) and (II) as a host component capable of sustaininghole-electron recombination and a guest fluorescent material capable ofemitting light in response to energy released by the hole-electronrecombination.

DESCRIPTION OF EMBODIMENTS

In aspects thereof, the present invention relates to an organicelectroluminescent device comprised of an anode and a cathode, and an ELelement positioned between the anode and the cathode, wherein the ELelement has at least a light emitting layer containing a luminescenthydrocarbon compound of the Formula (I)

wherein R¹ and R² are substituents, which may be selected from the groupconsisting of hydrogen, an alkyl group with, for example, from 1 toabout 6 carbon atoms, an aryl group with about 6 to about 30 carbonatoms, an alkoxy group with preferably from 1 to about 6 carbon atoms, ahalogen, a cyano group and the like. Specific examples of substituentsfor R¹ and R² are hydrogen, methyl, tert-butyl, a phenyl, a biphenylyl,and the like; Ar¹ and Ar² in Formula (I) are each an aromatic component,such as an aryl group with, for example, about 4 to about 10conjugate-bonded or fused benzene rings, and which may be independentlyselected, for example, from the group consisting of those of thefollowing formulas

wherein R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ are each a substituent selected fromthe group consisting of hydrogen, an alkyl group with, for example,preferably from 1 to about 6 carbon atoms, an alicyclic alkyl group withfrom about 3 to about 15 carbon atoms, an alkoxy group with, forexample, preferably from 1 to about 6 carbon atoms, a dialkylamino groupwith preferably from about 1 to about 3 carbon atoms, a halogen, a cyanogroup and the like. Illustrative examples of alkyl group are methyl,ethyl, tert-butyl and the like; illustrative examples of alicyclic alkylgroup are cyclopentyl, cyclohexyl, 4-tert-butylcyclohexyl, and the like;typical examples of alkoxy group include methoxy, ethoxy, isopropoxy,tert-butoxy, and the like. Useful examples of substituents for R₁₁, R₁₂,R₁₃, R₁₄, and R₁₅ include hydrogen, methyl, tert-butyl, cyclohexyl,methoxy, tert-butoxy, fluorine, cyano and the like.

Also, in embodiments the present invention is directed to anelectroluminescent device comprised of a first electrode like an anode,an organic electroluminescent element, and a second electrode like acathode wherein said electroluminescent element contains a fluorescenthydrocarbon component of Formula (I)

wherein R¹ and R² are substituents selected from the group consisting ofhydrogen, an alkyl, an alicyclic alkyl, an alkoxy, a halogen, and acyano; Ar¹ and Ar² are each independently an aromatic component or anaryl group comprised, for example, of from about 4 to about 15conjugate-bonded or fused benzene rings; an electroluminescent devicewherein Ar¹ and Ar² are independently selected from the group consistingof

wherein R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ are each a substituent selected fromthe group consisting of hydrogen, alkyl with, for example, from 1 toabout 6 carbon atoms, an alicyclic alkyl group with, for example, fromabout 3 to about 15 carbon atoms, an alkoxy group with from 1 to about 6carbon atoms, a dialkylamino group with from about 2 to about 6 carbonatoms, a halogen, and a cyano group; an electroluminescent devicewherein the R¹ and R² are individually selected from the groupconsisting of methyl, ethyl, isopropyl, tert-butyl, cyclohexyl,4-tert-butylcyclohexyl, methoxy, ethoxy, isopropoxy, tert-butoxy,dimethylamino, diethylamino, phenyl, tolyl, naphthyl, anthryl,phenylanthryl, diphenylanthryl, biphenylyl, phenylvinyl, diphenylvinyl,hydrogen, fluorine, chlorine, and cyano; an electroluminescent devicewherein the R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ are individually selected fromthe group consisting of hydrogen, methyl, ethyl, isopropyl, tert-butyl,cyclohexyl, 4-tert-butylcyclohexyl, methoxy, ethoxy, isopropoxy,tert-butoxy, dimethylamino, diethylamino, fluorine, chlorine, and cyano;an electroluminescent device wherein the hydrocarbon component isselected from the group consisting of

an electroluminescent device comprised of an anode, an organicelectroluminescent element and a cathode, wherein the electroluminescentelement is situated between the anode and the cathode, and contains afluorescent hydrocarbon component of Formula (II)

hydrogen, an alkyl group, an alicyclic alkyl group, an aryl group, analkoxy group, a halogen, and a cyano group; R³, R⁴, R⁵, and R⁶ areindependently selected from the group consisting of hydrogen, an alkylgroup, an alicyclic alkyl group, an aryl group, and an alkoxy group,wherein R³ and R⁴, or R⁴ and R⁵ are optionally combined into a bivalenthydrocarbon group selected from the group consisting of an alkylene, analkylidene, an alicyclic alkylidene, and an arylalkylidene, wherein Ar¹and Ar² are independently an aryl group; and wherein Ar is antetravalent aromatic group; an electroluminescent device wherein the R¹and R² are individually selected from the group consisting of methyl,ethyl, cyclohexyl, tert-butyl, methoxy, ethoxy, tert-butoxy, phenyl,tolyl, hydrogene, fluorine, chlorine, and cyano; an electroluminescentdevice wherein the R³, R⁴, R⁵ and R⁶ are selected from the groupconsisting of hydrogen, methyl, ethyl, propyl, hexyl, cyclohexyl,tert-butyl, methoxy, ethoxy, 2-methoxyethyl, phenyl, tolyl,methoxyphenyl, cyclohexylidene, 4-tert-butylcyclohexylidene,benzylidene, diphenylmethylidene, and mixtures thereof; anelectroluminescent device wherein Ar¹ and Ar² are selected from thegroup consisting of an aryl of phenyl, tolyl, tert-butylphenyl,methoxyphenyl, 3,5-diphenylphenyl, 3,5-bis(p-tert-butylphenyl)phenyl,biphenylyl, and 4′-methoxybiphenyl-4-yl, 2-phenylvinyl,2,2-diphenylvinyl, and trans-stilbenyl; an electroluminescent devicewherein R₁ to R₆ are each a substituent selected from the groupconsisting of hydrogen, an alkyl group with from 1 to about 6 carbonatoms, an alicyclic alkyl group with from about 3 to about 15 carbonatoms, an alkoxy group with from 1 to about 6 carbon atoms, adialkylamino group with from about 1 to about 3 carbon atoms, a halogen,and cyano; an electroluminescent device wherein the substituents for R₁to R₆ are individually selected from the group consisting of hydrogen,methyl, ethyl, isopropyl, tert-butyl, cyclohexyl,4-tert-butylcyclohexyl, methoxy, ethoxy, isopropoxy, tert-butoxy,dimethylamino, diethylamino, fluorine, chlorine, and cyano; anelectroluminescent device wherein the hydrocarbon component is selectedfrom the group consisting of

an electroluminescent device wherein the electroluminescent elementincludes an emitting layer comprised of a host hydrocarbon compoundcomprised of Formula (I), (II), or mixtures thereof, and a fluorescentdye; an electroluminescent device wherein the fluorescent dye possessesa bandgap no greater than that of the host material; anelectroluminescent device wherein the fluorescent dye is selected fromthe group consisting of coumarins, dicyanomethylene pyranes,polymethines, oxabenzanthranes, xanthenes, pyryliums, carbostyls,perylenes, acridones, quinacridone, and fused ring aromatic fluorescentdyes; an electroluminescent device wherein the fluorescent dye isselected from the group consisting of N-methyl-9-acridone,N-methyl-2-methoxy-9-acridone, N-methyl-2-phenoxy-9-acridone,N-methyl-2-t-butoxy-9-acridone, N-phenyl-2-methoxy-9-acridone,N-methyl-2-phenyl-9-acridone, N-methyl-2-diethylamino-9-acridone,perylene, terta-tert-butylperylene, rubrene, N,N′-dimethylquinacridone,N,N′-dimethyl-2-methylquinacridone,N,N′-dimethyl-2,9-dimethylquinacridone,N,N′-dimethyl-2-chloroquinacridone, N,N′-dimethyl-2-fluoroquinacridone,and N,N′-dimethyl-1,2-benzoquinacridone; an electroluminescent devicewherein the fluorescent dye is present in an amount of from about 10⁻³to about 10 mole percent based on the moles of the hydrocarbon hostmaterial; an organic electroluminescent device comprising in thefollowing sequence an anode, an optional buffer layer, a holetransporting layer, a light emitting layer comprised of a hydrocarboncompound of Formulas (I), (II) or mixtures thereof, an electrontransport layer, and a cathode; an electroluminescent device wherein thebuffer layer is comprised of a phthalocyanine derivative, and whereinthe hole transport layer is comprised of a tertiary aromatic amine; anelectroluminescent device wherein the tertiary aromatic amine isN,N′-di-1-naphthyl-N,N′-diphenyl-benzidine; an electroluminescent devicewherein the electron transport layer is comprised oftri(8-hydroxyquinolinato)aluminum; an electroluminescent device whereinthe electron transport layer is comprised of triazines, or a triazine;an electroluminescent device wherein the triazine is selected from thegroup consisting of4,4′-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-p-tolyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-m-tolyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-p-methoxyphenyl-1,3,5-triazinyl)]-1,1′-biphenyl, and2,4,6-tri(1,1′-biphenyl-4-yl)-1,3,5-triazine; an electroluminescentdevice wherein the light emitting layer further includes a fluorescentdye; an electroluminescent device wherein the fluorescent dye isselected from the group consisting of 9-acridones, quinacridones, andperylenes; an electroluminescent device wherein the light emitting layeris comprised of a mixture of hydrocarbon compounds of Formulas (I),(II), or mixtures thereof, and wherein the second hydrocarbon (II) ispresent in an amount of from about 1 to about 50 mole percent based onthe mole percent of the first hydrocarbon compound, and wherein thetotal of (I) and (II) is about 100 percent; an electroluminescent devicewherein the anode is comprised of indium tin oxide in a thickness offrom about 1 to about 500 nanometers; the buffer layer is comprised of aphthalocyanine in a thickness of from about 5 to about 80 nanometers,the hole transport layer is comprised of a tertiary aromatic amine in athickness of from about 5 to about 300 nanometers; the light emittinghydrocarbon layer is of a thickness of about 5 to about 300 nanometers,and the cathode is comprised of a magnesium silver alloy or a lithiumaluminum alloy in a thickness of from about 10 to about 800 nanometers;an electroluminescent device wherein the element is a layer, the firstelectrode is an anode, and the second electrode is a cathode; anelectroluminescent device wherein the element is comprised of a layeredelectroluminescent arrangement comprised of a hole transport layer, anda light emitting layer wherein optionally hydrocarbon compounds areadded thereto, and an electron transport layer; and which element ispositioned in between the anode and cathode; an electroluminescentdevice wherein the element represents a single layer, a plurality oflayers, or a plurality of laminated layers; an electroluminescent devicewherein the electron transport layer is comprised oftri(8-hydroxyquinolinato)aluminum, or a triazine; an electroluminescentdevice wherein the light emitting layer further includes a fluorescentdye; an electroluminescent device and further including an electrontransport layer wherein the hole transport layer is comprised of atertiary aromatic amine; an electroluminescent device wherein the firstelectrode is an anode of indium tin oxide, the hole transport is atertiary aromatic amine, the light emitting hydrocarbon is of athickness of from about 5 to about 300 nanometers, and the secondelectrode is a cathode of a metal alloy; a compound of Formulas (I),(II), or mixtures thereof; a compound of the Formulas

wherein R¹ and R² are substituents, which are selected from the groupconsisting of hydrogen, an alkyl, an alicyclic alkyl, an alkoxy, ahalogen, and a cyano; Ar¹ and Ar² are each independently an aromaticcomponent or an aryl group comprised of a from about 4 to about 15conjugate-bonded or fused benzene rings; or

wherein R¹ and R² are independently selected from the group consistingof hydrogen, an alkyl group, an alicyclic alkyl group, an aryl group, analkoxy group, a halogen, a cyano group; R³, R⁴, R⁵, and R⁶ areindependently selected from the group consisting of hydrogen, an alkylgroup, an alicyclic alkyl group, an aryl group, and an alkoxy group;wherein R³ and R⁴, or R⁴ and R⁵ are optionally combined into a bivalenthydrocarbon group selected from the group consisting of an alkylene, analkylidene, an alicyclic alkylidene, and an arylalkylidene; wherein Ar¹and Ar² are independently an aryl group; and wherein Ar is a tetravalentaromatic group; an organic electroluminescent device wherein the firstelectrode is an anode and the second electrode is a cathode.

Illustrative examples of the hydrocarbon compounds encompassed byFormula (I) include the following

The present invention also relates to an organic electroluminescentdevice comprised of an anode and a cathode, and an EL element positionedbetween the anode and the cathode, wherein said EL element has at leastone light emitting layer containing a luminescent hydrocarbon compoundcomprised of the Formula (II)

wherein R¹ and R² are substituents, which may be selected from the groupconsisting of hydrogen, an alkyl group with, for example, from 1 toabout 6 carbon atoms, an alicyclic alkyl group with from about 3 toabout 15 carbon atoms, an aryl group with about 6 to about 30 carbonatoms, an alkoxy group with preferably from 1 to about 6 carbon atoms, ahalogen, a cyano group and the like; illustrative examples of alkylgroup are methyl, ethyl, tert-butyl and the like. Illustrative examplesof alicyclic alkyl group are cyclopentyl, cyclohexyl,4-tert-butylcyclohexyl, and the like; examples of aryl for R¹ and R²include a phenyl, a tolyl, 4-tert-butylphenyl, and the like; typicalexamples of alkoxy group include methoxy, ethoxy, isopropoxy,tert-butoxy, and the like. R³, R⁴, R⁵, and R⁶ are each a substituent,which may be selected from the group consisting of hydrogen, an alkylgroup with, for example, from 1 to about 6 carbon atoms, an alicyclicalkyl group with from about 3 to about 15 carbon atoms, an aryl groupwith about 6 to about 30 carbon atoms, an alkoxy group with preferablyfrom 1 to about 6 carbon atoms, and the like. Illustrative examples ofsubstituents include hydrogen, methyl, ethyl, tert-butyl, cyclopentyl,cyclohexyl, 4-tert-butylcyclohexyl, a phenyl, a tolyl,4-tert-butylphenyl, 4-methoxyphenyl, methoxy, ethoxy, propoxy, butoxy,and the like. R³ and R⁴, or R⁴ and R⁵ may combined into a bivalenthydrocarbon group being selected from, for example, the group consistingof an alkylene group with from about 3 to about 8 carbon atoms, analkylidene group with from about 3 to about 15 carbon atoms, analicyclic alkylidene group with from about 3 to about 15 carbon atoms,and an arylalkylidene group with from about 6 to about 30 carbon atoms,and the like. Illustrative examples of bivalent group for R³ and R⁴, orR⁴ and R⁵ include 1,5-pentylene, 1,6-hexalene, ethylidene,phenylmethylidene, diphenylmethylidene, cyclohexalidene,4-tert-butylcyclohexalidene, and the like.

Ar¹ and Ar² are each an aromatic component, such as an aryl group withfrom about 6 to about 30 carbon atoms, or an arylvinyl group with fromabout 6 to about 30 carbon atoms, which may, for example, be selectedfrom the group consisting of a phenyl, a biphenylyl, a 3,5-diarylphenyl,a phenylvinyl, a diphenylvinyl, and the like. Illustrative examples ofaryl groups for Ar¹ and Ar² are a phenyl, p-tert-butylphenyl,p-methoxyphenyl, 3,5-diphenylphenyl, 3,5-bis(p-tert-butylphenyl)phenyl,biphenylyl, 4′-methoxybiphenyl-4-yl, 2-phenylvinyl, 2,2-diphenylvinyl,and the like.

Ar for Formula (II) is in embodiments a tetravalent aromatic group with,for example, from about 6 to about 60 carbon atoms, and which group maybe selected, for example, from the group consisting of

wherein R₁₁, R₁₂, and R₁₃ are each a substituent, which may be selectedfrom the group consisting of hydrogen, an alkyl group with, for example,from 1 to about 6 carbon atoms, an alicyclic alkyl group with, forexample, from about 3 to about 15 carbon atoms, an alkoxy group with,for example, from about 1 to about 6 carbon atoms, a dialkylamino groupwith from about 1 to about 3 carbon atoms, a halogen, a cyano group andthe like. Illustrative examples of substituents for R₁₁, R₁₂, R₁₃include hydrogen, methyl, tert-butyl, cyclohexyl, methoxy, tert-butoxy,fluorine, cyano and the like.

Examples of specific hydrocarbon compounds illustrated by Formula (II)include

The hydrocarbon compounds may be generated by a number of syntheticprocesses. For example, they can be synthesized as follows: a mixtureconsisting of one equivalent of a suitable dibromoarene compound or anarene ditriflate compound, such as 4,4′-(9-fluorenylidene)diphenylditriflate, two equivalents of a base, such as potassium carbonate, twoequivalents of an arene diborate compound, such as9-anthryl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 0.01 equivalent of apalladium catalyst, such as tetrakis(triphenylphosphine)palladium, andsuitable amounts of an inert solvent, such as dioxane, is heated underargon to reflux for a suitable time, about 48 hours. After cooling toroom temperature, about 23° C., the reaction contents are added intomethanol or water, and the precipitate is collected by filtration. Theproduct may further be purified by standard purification means includingrecrystallization and sublimation. The hydrocarbon compounds thusobtained may be confirmed by elemental analysis, NMR or IR spectrometricidentification techniques.

The luminescent hydrocarbon materials described herein exhibit strongfluorescence in the solid state in the region from about 400 nanometersto, for example, about 600 nanometers. They have the ability of formingthin films with excellent thermal stability by vacuum evaporation.

In embodiments, the light emitting layer 5 disclosed herein may furtherinclude a fluorescent material, wherein the layer is formed of aluminescent composition comprised of a hydrocarbon compound illustratedby Formulas through (I) or (II) as a host component and a guestfluorescent material. By mixing with the hydrocarbon host component asmall amount of a fluorescent material capable of emitting light inresponse to hole-electron recombination, improved device performancecharacteristics, such as emission hue and electroluminescent efficiency,may be achieved. The fluorescent material is present in an amount of,for example, from about 0.01 to about 10 weight percent, or from about10⁻³ to about 10 mole percent, based on the moles of the hydrocarbonhost material, and preferably from about 1 to about 5 weight percent ofthe host hydrocarbon component. Suitable fluorescent material employedas the guest component are those possessing, for example, a bandgap nogreater than that of said host component and a potential less negativethan that of the host component. The fluorescent materials can beblended with the host hydrocarbon material to form a common phase.

Illustrative examples of fluorescent materials are dyes selected, forexample, from the group consisting of coumarin, dicyanomethylenepyranes, polymethine, oxabenzanthrane, xanthene, pyrylium, carbostyl,perylene, and the like; preferable examples of fluorescent materialsinclude acridone dyes such as N-methyl-9-acridone,N-methyl-2-methoxy-9-acridone, N-methyl-2-phenoxy-9-acridone,N-methyl-2-t-butoxy-9-acridone, N-phenyl-2-methoxy-9-acridone,N-methyl-2-phenyl-9-acridone, N-methyl-2-diethylamino-9-acridone, andthe like; a dye selected from the group consisting of quinacridonederivatives; illustrative examples of quinacridone dyes include ofN,N′-dimethylquinacridone, N,N′-dimethyl-2-methyl quinacridone,N,N′-dimethyl-2,9-dimethylquinacridone,N,N′-dimethyl-2-chloroquinacridone, N,N′-dimethyl-2-fluoroquinacridone,and N,N′-dimethyl-1,2-benzoquinacridone, and the like. Also, anotherpreferred class of fluorescent materials is fused ring fluorescent dyes.Examples of the fused ring fluorescent dyes include perylene,tetra-t-butylperylene, rubrene, anthracene, coronene, phenanthrecene,pyrene and the like, as illustrated in U.S. Pat. No. 3,172,862, thedisclosure of which is totally incorporated herein by reference. Also,fluorescent materials that can be selected as a dopant includebutadienes, such as 1,4-diphenylbutadiene, tetraphenylbutadiene,stilbenes, and the like, as illustrated in U.S. Pat. Nos. 4,356,429 and5,516,577, the disclosures of which are totally incorporated herein byreference.

The light emitting layer herein may be formed by any convenient manner.For example, it can be prepared by vacuum deposition from theevaporation of the luminescent hydrocarbon compound, or from thesimultaneous evaporation of the hydrocarbon host material and thefluorescent material. The thickness of the light emitting layer is notparticularly limited, and can range from about 5 nanometers to about 300nanometers, or from about 10 nanometers to about 100 nanometers.

It is desirable that the organic EL devices of the present inventioncomprise a supporting substrate. Illustrative examples of the supportingsubstrate include polymeric components, glass, and the like, andpolyesters like MYLAR®, polycarbonates, polyacrylates,polymethacrylates, polysulfones, quartz, and the like. Other substratescan also be selected provided, for example, they can effectively supportthe other layers, and that it does not interfere with the devicefunctional performance. The thickness of the substrate can be, forexample, from about 25 to about 1,000 microns or more, and for example,from about 50 to about 500 microns depending, for example, on thestructural demands of the device.

Examples of the anode, which is contiguous to the substrate, includepositive charge injecting electrodes, such as indium tin oxide, tinoxide, gold, platinum, or other suitable materials, such as electricallyconductive carbon, π-conjugated polymers such as polyaniline,polypyrrole, and the like with, for example, a work function equal to,or greater than about 4 electron volts, and more specifically, fromabout 4 to about 6 electron volts. The thickness of the anode can rangefrom about 1 to about 5,000 nanometers with the preferred range beingdictated by the optical constants of the anode material. One preferredrange of thickness is from about 30 to about 100 nanometers.

The buffer layer is optional, and which layer primarily functions toachieve desirable charge injection of holes from the anode, and toimprove the adhesion between the anode and the organic hole transportinglayer, thus further improving the device operation stability. Specificexamples of buffer layer materials include conductive materials, such aspolyaniline and its acid-doped forms, polypyrrole, poly(phenylenevinylene), and known semiconductive organic materials; porphyrinderivatives disclosed in U.S. Pat. No. 4,356,429, such as1,10,15,20-tetraphenyl-21H,23H-porphyrin copper (II); copperphthalocyanine, copper tetramethyl phthalocyanine; zinc phthalocyanine;titanium oxide phthalocyanine; magnesium phthalocyanine; and the like,the disclosures of each of these patents being totally incorporatedherein by reference.

A class of hole transporting materials that can be selected for thebuffer layer are the aromatic tertiary amines, such as those disclosedin U.S. Pat. No. 4,539,507, the disclosure of which is totallyincorporated herein by reference. Representative examples of aromatictertiary amines are bis(4-dimethylamino-2-methylphenyl)phenylmethane,N,N,N-tri(p-tolyl)amine, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane,1,1-bis(4-di-p-tolylamino phenyl)-4-phenyl cyclohexane,N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine,N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine,N,N′-diphenyl-N,N′-bis(4-methoxyphenyl)-1,1′-biphenyl-4,4′-diamine,N,N,N′,N′-tetra-p-tolyl-1,1′-biphenyl-4,4′-diamine,N,N′-di-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl4,4′-diamine, and thelike. Another class of aromatic tertiary amines selected for the holetransporting layer is polynuclear aromatic amines, such asN,N-bis-[4′-(N-phenyl-N-m-tolylamino)-4-biphenylyl]aniline;N,N-bis-[4′-(N-phenyl-N-m-tolylamino)4-biphenylyl]-m-toluidine;N,N-bis-[4′-(N-phenyl-N-m-tolylamino)-4-biphenylyl]-p-toluidine;N,N-bis-[4′-(N-phenyl-N-p-tolylamino)-4-biphenylyl]aniline;N,N-bis-[4′-(N-phenyl-N-p-tolylamino)-4-biphenylyl]-m-toluidine;N,N-bis-[4′-(N-phenyl-N-p-tolylamino)-4-biphenylyl]-p-toluidine;N,N-bis-[4′-(N-phenyl-N-p-chlorophenylamino)-4-biphenylyl]-m-toluidine;N,N-bis-[4′-(N-phenyl-N-m-chlorophenylamino)-4-biphenylyl]-m-toluidine;N,N-bis-[4′-(N-phenyl-N-m-chlorophenylamino)-4-biphenylyl]-p-toluidine;N,N-bis-[4′-(N-phenyl-N-m-tolylamino)-4-biphenylyl]-p-chloroaniline;N,N-bis-[4′-(N-phenyl-N-p-tolylamino)-4-biphenylyl]-m-chloroaniline;N,N-bis-[4′-(N-phenyl-N-m-tolylamino)-4-biphenylyl]-1-aminonaphthaleneand the like.

The buffer layer comprised of aromatic tertiary amines described hereinmay further include, as disclosed in U.S. Pat. No. 5,846,666, thedisclosure of which is totally incorporated herein by reference, astabilizer comprised of certain hydrocarbon compounds, such as rubrene,4,8-diphenylanthracene, and the like. The buffer layer can be preparedby forming a suitable compounds into thin film by known methods, such asvapor deposition or spin-coating. The thickness of buffer layer thusformed is not particularly limited, and can be in a range of from about5 nanometers to about 300 nanometers, and preferably from about 10nanometers to about 100 nanometers.

The hole transporting layers can be comprised of a hole transportingmaterial with a thickness ranging, for example, from about 1 nanometerto about 200 nanometers, and preferably from about 5 nanometers to about100 nanometers. This layer can reduce the driving voltage of the deviceand improve the confinement of the injected charge recombination withinthe hydrocarbon light emitting layer. Any conventional suitable aromaticamine hole transporting materials described for the buffer layer may beselected for forming this layer.

A preferred class of hole transporting materials selected for formingthe hole transporting layer is comprised of N,N,N′,N′-tetraarylbenzidinederivatives. Illustrative examples of benzidine derivatives includeN,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine,N,N′-diphenyl-N,N′-bis(4-methoxyphenyl)-1,1′-biphenyl-4,4′-diamine,N,N,N′,N′-tetra-p-tolyl-1,1′-biphenyl-4,4′-diamine,N,N′-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine and the like.

The electron optional transporting layer selected for the primarypurpose of improving the electron injection characteristics and theemission uniformity of the EL devices of the present invention are of asuitable thickness, for example from about 1 nanometer to about 300nanometers, or from about 5 nanometers to about 100 nanometers.Illustrative examples of electron transporting compounds, which can beutilized in this layer, include the metal chelates of 8-hydroxyquinolineas disclosed in U.S. Pat. Nos. 4,539,507; 5,151,629, and 5,150,006, thedisclosures of which are totally incorporated herein by reference.Illustrative examples include tris(8-hydroxyquinolinate) aluminum, apreferred one, tris(8-hydroxyquinolinate) gallium,bis(8-hydroxyquinolinate) magnesium, bis(8-hydroxyquinolinate) zinc,tris(5-methyl-8-hydroxyquinolinate) aluminum,tris(7-propyl-8-quinolinolato) aluminum,bis[benzo{f}-8-quinolinate]zinc, bis(10-hydroxybenzo[h]quinolinate)beryllium, and the like. Another class of metal chelate compounds forelectron transport layer is the oxadiazole metal chelates disclosed inU.S. Pat. No. 5,925,472, the disclosures of which are totallyincorporated herein by reference.

Another class of electron transport materials comprises triazinecompounds as disclosed in U.S. Pat. No. 6,057,048, the disclosure ofwhich is totally incorporated herein by reference. Illustrative specificexamples include4,4′-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-p-tolyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-m-tolyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-p-anisyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4-β-naphthyl-6-phenyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-biphenylyl-1,3,5-triazinyl)]-1′-biphenyl,4,4′-bis-[2-(4,6-di-phenyl-1,3,5-triazinyl)]-2,2′-dimethyl-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-phenyl-1,3,5-triazinyl)]-stilbene,4,4′-bis-[2-(4-phenyl-6-p-tolyl-1,3,5-triazinyl)]-stilbene,2,4,6-tri(4-biphenylyl)-1,3,5-triazine, and the like.

The cathode can be comprised of any metal, including high, for examplefrom about 4.0 eV to about 6.0 eV, or low work function component, suchas metals with, for example, an eV of from about 2.5 eV to about 4.0 eV(electron volts). The cathode can be derived from a combination of a lowwork function metal (less than about 4 eV) and at least one other metal.Effective proportions of the low work function metal to the second orother metal are from less than about 0.1 percent to about 99.9 percentby weight. Illustrative examples of low work function metals includealkaline metals such as lithium or sodium, Group 2A or alkaline earthmetals such as beryllium, magnesium, calcium, or barium, and Group IIImetals including rare earth metals and the actinide group metals such asscandium, yttrium, lanthanum, cerium, europium, terbium, or actinium.Lithium, magnesium and calcium are preferred low work function metals.

The thickness of cathode ranges from, for example, about 10 nanometersto about 500 nanometers. The Mg:Ag cathodes of U.S. Pat. No. 4,885,211,the disclosure of which constitutes one preferred cathode, can beselected for the EL devices of the present invention. Another cathodeconstruction is described in U.S. Pat. No. 5,429,884, the disclosure ofwhich are totally incorporated herein by reference, wherein the cathodesare, for example, formed from lithium alloys with other high workfunction metals such as aluminum and indium.

Both the anode and cathode of the EL devices of the present inventionmay contain a protective coating thereon, and the anode and cathode canbe of any convenient forms. A thin conductive layer can be coated onto alight transmissive substrate, for example a transparent or substantiallytransparent glass plate or plastic film. The EL device can include alight transmissive anode formed from tin oxide or indium tin oxidecoated on a glass plate. Also, very thin, for example less than about200 Å, and more specifically, from about 75 to about 150 Angstroms,light-transparent metallic anodes can be used, such as gold, palladium,and the like. In addition, transparent or semitransparent thin layers,for example from 50 to about 175 Angstroms of conductive carbon orconjugated polymers such as polyaniline, polypyrrole, and the like canbe used as anodes. Any suitable light transmissive polymeric film can beemployed as the substrate. Additional suitable forms of the anode 3 andcathode 6 are illustrated in U.S. Pat. No. 4,885,211.

Aromatic refers, for example, to aryl, such as phenyl, and which arylcan contain, for example, from about 6 to about 72 carbon atoms;aliphatic refers, for example, to alkyl, and alkoxy, each with fromabout 1 to about 40, preferably about 25, and most preferably from about1 to about 6 carbon atoms; halogen refers, for example, to chloride,bromide, fluoride or iodide, and n is from about zero (0) to about 3.

The following Examples are provided to further illustrate variousspecies of the present invention, it being noted that these Examples areintended to illustrate and not limit the scope of the present invention.

EXAMPLE I Synthesis of 9-Anthryl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

To a solution of 9-bromoanthracene (9.73 grams) in 100 milliliters ofanhydrous diethyl ether were slowly added at about 0° C. 23 millilitersof 2M n-butyllithium hexane solution. After the addition, the reactionmixture was warmed to room temperature (about 23° C.) for 30 minutes.The resulting mixture was then cooled to around −30° C. and2-isopropoxy-4,4,5,5-tetramethyl-1,3,3-dioxaborolane (9.27 milliliters)was added through a syringe. The resulting reaction mixture was warmedto room temperature (about 23° C.), and stirred overnight (about 18hours throughout). After being diluted with 50 milliliters of hexane,the mixture resulting was filtered through celite. Removal of thesolvents under reduced pressure yielded a yellowish solid (6.70 grams)which contains more than 90 percent of9-anthryl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. The product may beused without further purification. This compound and its structure wasconfirmed by proton NMR analysis.

EXAMPLE II Synthesis of 4,4′-(9-Fluorenylidene)diphenyl Ditriflate

To a solution of 4,4′-(9-fluorenyledene)diphenol (10 grams) in 100milliliters of anhydrous pyridine were added at about 5° C. grams 11milliliters of triflic acid anhydride. After the addition, the reactionmixture was warmed to room temperature (about 23° C.) for 6 hours. Afterremoval of the pyridine under reduced pressure, the residue wasdissolved in 200 milliliters of dichloromethane, washed with 5 percentHCl aqueous solution, followed by washing with water. After removal ofthe solvents, the resulting crude residue was purified through a silicacolumn to yield 17.26 grams of 4,4′-(9-fluorenylidene)diphenylditriflate. This compound and its structure was confirmed by proton NMRanalysis.

EXAMPLE III Synthesis of 9,9-bis[4-(9-Anthryl)phenyl) Fluorene

A mixture of 9-anthryl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (5grams), 4,4′-(9-fluorenylidene)diphenyl ditriflate (5.3 grams),potassium carbonate (2.27 grams) in 50 milliliters of dioxane was purgedwith argon for 10 minutes. To this mixture was then addedtetrakis(triphenylphosphine) palladium (0.37 gram). The reaction mixturewas stirred at reflux for 48 hours under argon. After cooling to roomtemperature (about 23° C.), the mixture was diluted with 30 millilitersof methanol, and the precipitates were collected by filtration, washedwith 5 percent HCl aqueous solution, followed by water to removeinorganic salts. After drying, the filtrates were purified bysublimation to yield 2.5 grams of 9,9-bis[4-(9-anthryl)phenyl) fluorene.This compound had a melting point of 425° C. The structure of thiscompound was confirmed by proton NMR and elemental analysis.

EXAMPLE IV Synthesis of 10-Bromo-9-phenylanthracene

To a solution of 9-phenylanthracene (10 grams) and ferric chloride(0.065 gram) in 100 milliliters of dichloromethane were added 6.70 gramsof bromine in 30 milliliters of dichloromethane through an additionfunnel at room temperature. The reaction mixture was stirred for 3hours, and then washed with aqueous sodium thiosulfate and water. Afterremoval of the solvents, the crude residue was recrystallized fromethanol to yield 12.5 grams of 10-bromo-9-phenylanthracene. Thestructure of this compound was confirmed by proton NMR analysis.

EXAMPLE V Synthesis of9-(10-Phenylanthryl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

To a solution of 10-bromo-9-phenylanthracene (8.69 grams) in 100milliliters of anhydrous diethyl ether were slowly added at about 0° C.16 milliliters of 2M n-butyllithium hexane solution. After the addition,the reaction mixture was warmed to room temperature (about 23° C.) for30 minutes. The resulted mixture was then cooled to around −30° C. and2-isopropoxy-4,4,5,5-tetramethyl-1,3,3-dioxaborolane (6.49 milliliters)was added through a syringe. The reaction mixture was warmed to roomtemperature (about 23° C.), and stirred overnight, about 18 hours. Afterbeing diluted with 50 milliliters of hexane, the mixture was filteredthrough celite. Removal of the solvents under reduced pressure yielded ayellowish solid (7.90 grams) which contains more than 90 percent of9-(10-phenylanthryl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. Theproduct may be used without further purification. The structure of thiscompound was confirmed by proton NMR analysis.

EXAMPLE VI Synthesis of 9,9-bis[4-(10-Phenyl-9-anthryl)phenyl]fluorene

A mixture of9-(10-phenylanthryl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (3.8grams), 4,4′-(9-fluorenylidene)diphenyl ditriflate (3.23 grams),potassium carbonate (1.38 grams) in 50 milliliters of dioxane was purgedwith argon for 10 minutes. To this mixture was then addedtetrakis(triphenylphosphine)palladium (0.23 gram). The reaction mixturewas stirred at reflux for 48 hours under argon. After cooling to roomtemperature (about 23° C.), the mixture was diluted with 30 millilitersof methanol, and the precipitates were collected by filtration, washedwith 5 percent HCl aqueous solution followed by washing with water toremove inorganic salts. After drying, the filtrates were purified bysublimation to yield 1.5 grams of 9,9-bis[4-(9-anthryl)phenyl) fluorene,with a melting point of 518° C. The structure of this compound wasconfirmed by proton NMR and elemental analysis.

EXAMPLE VII Synthesis of6,6,12,12-Tetramethyl-2,8-diphenylindeno[1,2b]fluorene

This compound may be prepared in accordance to the procedure describedin J. Org. Chem., Vol. 56, 1210 (1991)(2,8-diphenyl-6,12-dihydroindeno[1,2b]fluorene, followed bymethylation).

EXAMPLE VIII

Organic EL devices comprising a light emitting layer of a fluorescenthydrocarbon compound of Formulas I, II or mixtures thereof, and morespecifically, with the hydrocarbon of Example III can be fabricated inthe following manner:

1. A 500 Å indium tin oxide (ITO) anode coated glass substrate wasselected, the thickness of the glass substrate being about 1 millimeter.The glass was cleaned with a commercial detergent, rinsed with deionizedwater and dried in a vacuum oven at 60° C. for 1 hour. Immediatelybefore use, the glass was treated with UV ozone for 0.5 hour.

2. The ITO anode coated on the glass substrate was then placed in avacuum deposition chamber, and a buffer layer was applied. The bufferlayer deposition rate and layer thickness were controlled by an InficonModel IC/5 controller. Under a pressure of about 5×10⁻⁶ Torr, a 15nanometers thick buffer layer was deposited on the ITO glass substratethrough evaporation of copper (II) phthalocyanine at a rate of 0.6nanometer/second from a tantalum boat.

3. Onto the buffer layer, a 20 nanometers thick hole transport layer ofN,N′-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine was depositedat a rate of 0.6 nanometer/second.

4. Onto the hole transport layer was deposited by evaporation a 40nanometers light emitting layer of 9,9-bis[4-(9-anthryl)phenyl)fluoreneat a rate of 0.6 nanometer/second.

5. A 20 nanometers thick electron transport layer of4,4′-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′-biphenyl was thendeposited by evaporation at a rate of 0.6 nanometer/second onto thelight emitting layer.

6. A 100 nanometer cathode of a magnesium silver alloy was deposited ata total deposition rate of 0.5 nanometer/second onto the light emittinglayer above by the simultaneous evaporation from two independentlycontrolled tantalum boats containing Mg and Ag, respectively. A typicalcomposition was 9:1 in atomic ratio of Mg to Ag. Finally, a 200nanometer silver layer was overcoated on the Mg:Ag cathode for theprimary purpose of protecting the reactive Mg from ambient moisture.

The EL device as prepared above were retained in a dry box which wascontinuously purged with nitrogen gas; their performance thereof wasassessed by measuring the current-voltage characteristics and lightoutput under a direct current measurement. The current-voltagecharacteristics were determined with a Keithley Model 238 High CurrentSource Measure Unit. The ITO electrode was always connected to thepositive terminal of the current source. At the same time, the lightoutput from the device was monitored by a silicon photodiode.

The light output from this device was 350 cd/m² when it was driven by adirect current of 25 mA/cm². The device emitted a blue emission with CIEcolor coordinates of X=0.158 and Y=0.151 measured by Minolta ChromameterCS-100.

EXAMPLE IX

This organic EL device utilizes an electron transport layer comprised ofa triazine and tri(8-hydroxyquinolinato)aluminum. The primary purpose ofusing triazine herein is to improve the chromaticity coordinates of blueemission color. The device can be fabricated in the following manner:

1. A 500 Å indium tin oxide (ITO) anode coated glass substrate wasselected, the thickness of the glass substrate being about 1 millimeter.The glass was cleaned with a commercial detergent, rinsed with deionizedwater and dried in a vacuum oven at 60° C. for 1 hour. Immediatelybefore use, the glass was treated with UV ozone for 0.5 hour.

2. The ITO anode coated on the glass substrate was then placed in avacuum deposition chamber, and a hole transport layer was applied. Thehole transport layer deposition rate and layer thickness were controlledby an Inficon Model IC/5 controller. Under a pressure of about 5×10⁻⁶Torr, a 30 nanometers thick hole transport layer ofN,N′-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine was depositedat a rate of 0.6 nanometer/second from a tantalum boat.

3. Onto the hole transport layer was deposited a 40 nanometers lightemitting layer of 9,9-bis[4-(9-anthryl)phenyl)fluorene at a rate of 0.6nanometer/second.

4. A total 30 nanometers thick electron transport layer was depositedonto the light emitting layer through first evaporation of a 10nanometers thick layer of tris(1,1′-biphenyl-4-yl)-1,3,5-triazine at arate of 0.6 nanometer/second, followed by evaporation of a 20 nanometersthick layer of tri(8-hydroxyquinolinato)aluminum at the same rate.

5. A 100 nanometer cathode of a magnesium silver alloy was deposited ata total deposition rate of 0.5 nanometer/second onto the light emittinglayer above by the simultaneous evaporation from two independentlycontrolled tantalum boats containing Mg and Ag, respectively. A typicalcomposition was 9:1 in atomic ratio of Mg to Ag. Finally, a 200nanometer silver layer was overcoated on the Mg:Ag cathode for theprimary purpose of protecting the reactive Mg from ambient moisture.

The light output from this device was 380 cd/m² when it was driven by adirect current of 25 mA/cm². The device emitted a blue emission with CIEcolor coordinates of X=0.156 and Y=0.140 measured by Minolta ChromameterCS-100.

EXAMPLES X TO XIII

These Examples illustrated organic EL devices containing a lightemitting layer comprised of a hydrocarbon host material and afluorescent guest material. The devices were fabricated in the followingmanner:

1. A 500 Å indium tin oxide (ITO) anode coated glass substrate wasselected, the thickness of the glass substrate being about 1 millimeter.The glass cleaned with a commercial detergent, rinsed with deionizedwater and dried in a vacuum oven at 60° C. for 1 hour. Immediatelybefore use, the glass was treated with UV ozone for 0.5 hour.

2. The ITO anode coated on the glass substrate was then placed in avacuum deposition chamber, and a hole transport layer was applied. Thehole transport layer deposition rate and layer thickness were controlledby an Inficon Model IC/5 controller. Under a pressure of about 5×10⁻⁶Torr, a 30 nanometers thick hole transport layer was deposited on theITO glass substrate through evaporation ofN,N′-1-naphthyl-N,N′-diphenyl-1,1′-biphenyl4,4′-diamine at a rate of 0.6nanometer/second from a tantalum boat.

3. Onto the hole transport layer were deposited a 42 nanometers thicklight emitting layer through simultaneous evaporation from twoindependently controlled tantalum boats of9,9-bis[4-(9-anthryl)phenyl]fluorene at a rate of 0.6 nanometer/second,and N-methyl-2-methoxy-9-acridone at such a rate that 1.6 weight percentor parts of this dye was doped.

4. A total 30 nanometers thick electron transport layer was depositedonto the light emitting layer through first evaporation of a 10nanometers thick layer of tris(1,1′-biphenyl-4-yl)-1,3,5-triazine at arate of 0.6 nanometer/second, followed by evaporation of a 20 nanometersthick layer of tri(8-hydroxyquinolinato)aluminum at the same rate.

5. A 100 nanometer cathode of a magnesium silver alloy was deposited ata total deposition rate of 0.5 nanometer/second onto the light emittinglayer above by the simultaneous evaporation from two independentlycontrolled tantalum boats containing Mg and Ag, respectively. A typicalcomposition was 9:1 in atomic ratio of Mg to Ag. Finally, a 200nanometer silver layer was overcoated on the Mg:Ag cathode for theprimary purpose of protecting the reactive Mg from ambient moisture.

The light output and CIE color coordinates from these devices weremeasured at a direct current of 25 mA/cm². The results are shown in thefollowing Table.

Light output Dopant (cd/m{circumflex over ( )}2) Example (percent) (25mA/cm{circumflex over ( )}2) CIE (X, Y) X 0 350 0.159, 0.147 XI 0.27 4140.155, 0.133 XII 0.8 395 0.152, 0.122 XIII 1.6 373 0.150, 0.112

EXAMPLE XIV

This EL device was fabricated in accordance with, that is repeating theprocess of Example VIII except that9,9-bis[4-(10-phenyl-9-anthryl)phenyl]fluorene was used in place of9,9-bis[4-(9-anthryl)phenyl]fluorene to form the light emitting layer.The light output from this organic EL device was 330 cd/m² when it wasdriven by a direct bias voltage of 8 volts. The device emitted agreenish blue color.

EXAMPLE XV

This Example illustrates an organic EL device containing alight-emitting layer comprised of a mixture of hydrocarbon compounds.The device was fabricated in accordance with Example VIII except thatthe light emitting layer described in Step 4 further included ahydrocarbon compound of 9,9-bis[4-(10-phenyl-9-anthryl)phenyl]fluorene.Thus, there were deposited onto the hole transporting layer throughsimultaneous evaporation 75 parts of9,9-bis[4-(9-anthryl)phenyl]fluorene at a rate of 0.6 nanometer/secondand 25 weight percent or parts of9,9-bis[4-(10-phenyl-9-anthryl)phenyl]fluorene at a rate of 0.2nanometer/second from two independently controlled tantalum boats. Whendriven by a direct bias voltage of 25 mA/cm², this organic EL deviceprovided a blue emission of about 380 cd/m².

EXAMPLE XVI

This EL device was fabricated in accordance with Example VIII exceptthat 6,6,12,12-tetramethyl-2,8-diphenylindeno[1,2b]fluorene was used inplace of 9,9-bis[4-(9-anthryl)phenyl]fluorene to form the light emittinglayer. When driven by a direct bias voltage of 25 mA/cm², this organicEL device provided a blue emission of about 320 cd/m².

EXAMPLE XVII

This Example illustrates an organic EL device containing alight-emitting layer comprised of a mixture of hydrocarbon compounds.The device was fabricated in accordance with Example VIII except thatonto the hole transporting layer was deposited a 40 nanometers thicklight emitting layer through simultaneous evaporation of about 85 weightpercent of 6,6,12,12-tetramethyl-2,8-diphenylindeno[1,2b]fluorene at arate of 0.6 nanometer/second and about 15 weight percent or parts of9,9-bis[4-(10-phenyl-9-anthryl)phenyl]fluorene at a rate of 0.1nanometer/second from two independently controlled tantalum boats. Whendriven by a direct bias voltage of 25 mA/cm², this organic EL deviceprovided a blue emission of about 370 cd/m².

Other modifications of the present invention will or may occur to thoseof ordinary skill in the art subsequent to a review of the presentapplication. These modifications and equivalents thereof are intended tobe included within the scope of the present invention.

What is claimed is:
 1. An electroluminescent device comprised of a firstelectrode, an organic electroluminescent element, and a second electrodewherein said electroluminescent element contains a fluorescenthydrocarbon component of Formula (I)

wherein R¹ and R² are substituents selected from the group consisting ofhydrogen, an alkyl, an alicyclic alkyl, an alkoxy, a halogen, and acyano; and wherein said Ar¹ and Ar² are independently selected from thegroup consisting of

wherein R₁₁, R₁₂, R₁₃, R₁₄, and R¹⁵ are each a substituent selected fromthe group consisting of hydrogen, alkyl with from 1 to about 6 carbonatoms, an alicyclic alkyl group with from about 3 to about 15 carbonatoms, an alkoxy group with from 1 to about 6 carbon atoms, adialkylamino group with from about 2 to about 6 carbon atoms, a halogen,and a cyano group.
 2. An electroluminescent device in accordance withclaim 1 wherein said R¹ and R² are individually selected from the groupconsisting of methyl, ethyl, isopropyl, tert-butyl, cyclohexyl,4-tert-butylcyclohexyl, methoxy, ethoxy, isopropoxy, tert-butoxy,dimethylamino, diethylamino, phenyl, tolyl, naphthyl, anthryl,phenylanthryl, diphenylanthryl, biphenylyl, phenylvinyl, diphenylvinyl,hydrogen, fluorine, chlorine, and cyano.
 3. An electroluminescent devicein accordance with claim 1 wherein said R₁₁, R₁₂, R₁₃, R₁₄, and R¹⁵ areindividually selected from the group consisting of hydrogen, methyl,ethyl, isopropyl, tert-butyl, cyclohexyl, 4-tert-butylcyclohexyl,methoxy, ethoxy, isopropoxy, tert-butoxy, diethylamino, fluorine,chlorine, and cyano.
 4. An electroluminescent device comprised of afirst electrode, an organic luminescent element, and a second electrodewherein said electroluminescent element contains a hydrocarbon componentselected from the group consisting of


5. An electroluminescent device in accordance with claim 1 wherein saidelectroluminescent element includes an emitting layer comprised of ahost hydrocarbon compound comprised of Formula (I), and a fluorescentdye.
 6. An electroluminescent device in accordance with claim 5 whereinsaid fluorescent dye possesses a bandgap no greater than that of thehost material.
 7. An electroluminescent device in accordance with claim5 wherein said fluorescent dye is selected from the group consisting ofcoumarins, dicyanomethylene pyranes, polymethines, oxabenzanthranes,xanthenes, pyryliums, carbostyls, perylenes, acridones, quinacridone,and fused ring aromatic fluorescent dyes.
 8. An electroluminescentdevice in accordance with claim 5 wherein said fluorescent dye isselected from the group consisting of N-methyl-9-acridone,N-methyl-2-methoxy-9-acridone, N-methyl-2-phenoxy-9-acridone,N-methyl-2-t-butoxy-9-acridone, N-phenyl-2-methoxy-9-acridone,N-methyl-2-phenyl-9-acridone, N-methyl-2-diethylamino-9-acridone,perylene, terta-tert-butylperylene, rubrene, N,N′-dimethylquinacridone,N,N′-dimethyl-2-methylquinacridone,N,N′-dimethyl-2,9-dimethylquinacridone,N,N′-dimethyl-2-chloroquinacridone, N,N′-dimethyl-2-fluoroquinacridone,and N,N′-dimethyl-1,2-benzoquinacridone.
 9. An electroluminescent devicein accordance with claim 5 wherein said fluorescent dye is present in anamount of from about 10⁻³ to about 10 mole percent based on the moles ofsaid hydrocarbon host material.
 10. An electroluminescent device inaccordance with claim 1 wherein said element is a layer, said firstelectrode is an anode, and said second electrode is a cathode.
 11. Anelectroluminescent device in accordance with claim 1 wherein saidelement is comprised of a layered electroluminescent arrangementcomprised of a hole transport layer, and a light emitting layer whereinhydrocarbon compounds are added thereto, and an electron transportlayer; and which element is positioned in between said first and secondelectrodes.
 12. An electroluminescent device in accordance with claim 1wherein said element represents a single layer, a plurality of layers,or a plurality of laminated layers.
 13. An electrolumindacent device inaccordance with claim 1 wherein said electroluminescent element furtherincludes a fluorescent dye.
 14. An electroluminescent device inaccordance with claim 1 and further including an electron transportlayer.
 15. An organic electroluminescent device in accordance with claim1 wherein said second electrode is an anode and said first electrode isa cathode.
 16. An organic electroluminescent device in accordance withclaim 1 and wherein said first electrode is an anode, said secondelectrode is a cathode, and which device further contains an electrontransport layer, a hole transport layer and a light emitting layer andfurther wherein said device contains a buffer layer.
 17. Anelectroluminescent device in accordance with claim 16 wherein said firstelectrode is an anode of indium tin oxide, said light emitting layer isof a thickness of from about 5 to about 300 nanometers, and said secondelectrode is a cathode of a metal alloy.
 18. An electroluminescentdevice in accordance with claim 17 wherein said buffer layer iscomprised of a phthalocyanine derivative, and wherein said holetransport layer is comprised of a tertiary aromatic amine.
 19. Anelectroluminescent device in accordance with claim 18 wherein saidtertiary aromatic amine is N,N′-di-1-naphthyl-N,N′-diphenyl-benzidine.20. An electroluminescent device in accordance with claim 17 whereinsaid electron transport layer is comprised oftri(8-hydroxyquinolinato)aluminum.
 21. An electroluminescent device inaccordance with claim 18 wherein said electron transport layer iscomprised of triazines, or a triazine.
 22. An electroluminescent devicein accordance with claim 21 wherein said triazine is selected from thegroup consisting of4,4′-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-p-tolyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-m-tolyl-1,3,5-triazinyl)]-1,1′-biphenyl,4,4′-bis-[2-(4,6-di-p-methoxyphenyl-1,3,5-triazinyl)]-1,1′-biphenyl, and2,4,6-tri(1,1′-biphenyl-4-yl)-1,3,5-triazine.
 23. An electroluminescentdevice in accordance with claim 17 wherein said light emitting layerfurther includes a fluorescent dye.
 24. An electroluminescent device inaccordance with claim 23 wherein said fluorescent dye is selected fromthe group consisting of 9-acridones, quinacridones, and perylenes. 25.An electroluminescent device in accordance with claim 17 wherein saidanode is comprised of indium tin oxide in a thickness of from about 1 toabout 500 nanometers; said buffer layer is comprised of a phthalocyaninein a thickness of from about 5 to about 80 nanometers, said holetransport layer is comprised of a tertiary aromatic amine in a thicknessof from about 5 to about 300 nanometers; said light emitting layer is ofa thickness of about 5 to about 300 nanometers, and said cathode iscomprised of a magnesium silver alloy or a lithium aluminum alloy in athickness of from about 10 to about 800 nanometers.